1. Field of the Invention
The present invention relates to a switch structure for a display screen, arranged to display an image indicating switch information on a display screen, and including a switch portion which is operated above the display screen.
The present application is based on Japanese Patent Application No. Hei. 10-371601, which is incorporated herein by reference.
2. Description of the Related Art
In recent years an attempt has been made to realize a switch having a multiplicity of functions. Therefore, a switch for a display screen has been suggested which displays an image indicating switch information displayed on the display screen of the display unit and which is operated above the display screen. The switch for the display screen includes a touch-panel-type switch in which a touch panel is disposed on the display screen and arranged to be depressed, and a contact-type switch in which a transparent operation member is provided for the display screen and arranged to be depressed to operate the switch. The touch panel switch has substantially no operation stroke when the depression is performed. Therefore, a satisfactory input feeling cannot be obtained. On the other hand, the switch structure including the transparent operation members and the contact-type switches permits a sufficiently long operation stroke when the depression is performed. Therefore, the foregoing problem can be overcome and a satisfactory input operability can be obtained.
An example of a switch structure for a display screen of the foregoing type is shown in FIGS. 16 and 17. Referring to FIGS. 16 and 17, a body 1 of the apparatus is provided with a display 2 for displaying an image indicating switch information. Transparent operation members 3 are disposed above a display screen 2a of the display 2 for displaying an image indicating switch information. An end of each of the transparent operation members 3 is rotatively supported by a display panel 4. A switch portion 5 is disposed between another end of each of the transparent operation members 3 and the body 1 of the apparatus. The image of the switch information displayed on the display 2 is transmitted through and also displayed on the surface side of the transparent operation member 3. Thus, a user recognizes the switch information, and then depresses the transparent operation member 3.
The above-mentioned switch structure for a display screen, however, has the thickness d from the display screen 2a of the display 2 to the surface of the transparent operation member 3. Therefore, when the user views the image of the switch information on the display 2 from a diagonal position, a dead area is produced on the display screen 2a, as shown in FIG. 16. The dead area is enlarged according to the angle of visibility. Therefore, when an attempt is made to maintain a wide angle of visibility of 45xc2x0 in each of right and left directions, 45xc2x0 in an upward direction and 10xc2x0 in a downward direction, the effective display area of the display 2 is made to be small area E indicated in faint black shown in FIG. 17. Therefore, there arises a problem in that the display area of the display 2 cannot effectively be used.
In order to effectively use the display area of the display 2, substantially the overall display area of the display 2 must be used as the effective display area. In order to maintain a required wide angle of visibility, the opened area of the transparent operation member 3 must considerably be enlarged. In the foregoing case, the transparent operation members 3 are excessively enlarged from a viewpoint of practical use.
If optical paths are formed in such a manner that light made incident on the transparent operation member 3 passes toward each end surface of the transparent operation members 3, another problem arises in that a ghost occurs according to the angle of viewing.
In view of the foregoing, it is an object of the present invention to provide a switch structure for a display screen, which is capable of maintaining a wide angle of visibility, permitting the display area of a display device to be used effectively and preventing occurrence of a ghost.
According to the first aspect of the present invention, there is provided a switch structure for a display screen which comprises a display device that includes a display screen and is capable of displaying on the display screen an image that indicates various information comprising switch information, a switch body disposed on the display device, the switch body being operative to be switched in one of an on state and an off state thereof, and a operation plate disposed above the display screen of the display device, wherein when the operation plate is depressed, the state of the switch body is switched, the operation plate including an optical portion through which an image indicating the switch information on the display screen is transmitted, the optical portion forming the transmitted image to enlarge a visible range with which the image is made to be visible. Accordingly, when an image of switch information is viewed from a right position or a left position, the dead area of the display screen can be reduced which is caused from the thickness from the display screen of the display device to the surface of the operation plate. Therefore, the ratio of the effective display area of the display device with respect to the opened area of the operation plate can be raised. As a result, a wide angle of visibility can be maintained and the display area of the display device can effectively be used.
According to the second aspect of the present invention, it is preferable that the optical portion of the operation plate has a concave lens. The foregoing switch structure is able to simplify the structure of the optical portion, in addition to the effect obtainable from the first aspect. Therefore, manufacturing and assembly can easily be performed.
According to the third aspect of the present invention, it is preferable that the operation plate further includes a switch depressing portion formed on one end of the optical portion, the switch depressing portion being disposed above the switch body, and a pivotally supporting portion provided adjacent to the other end of the optical portion, wherein the optical portion is pivotally supported by the pivotally supporting portion, and wherein when the optical portion is depressed, the state of the switch body is switched by the switch depressing portion. The foregoing switch structure has the structure that when the optical portion is depressed, the operation member is rotated relative to the pivotally supporting portion so that the switch depressing portion operates the switch body, in addition to the effect obtainable from the first aspect or the second aspect.
According to a fourth aspect of the present invention, it is preferable that the concave lens has a flat surface on one side thereof and a concave shape on an opposite side thereof facing the display screen. The foregoing switch structure facilitates the depressing operation because the side which is depressed by the finger is formed into the flat surface, in addition to the effect obtainable from the second aspect.
According to a fifth aspect of the present invention, it is preferable that the concave lens has a concave shape on one side thereof and also a concave shape on an opposite side thereof facing the display screen. The foregoing switch structure has the structure that the dead area on the display screen caused from the thickness from the display screen of the display unit to the surface of the operation member can furthermore be reduced and, therefore, the ratio of the effective display area of the display with respect to the opened area of the operation member can furthermore be raised in addition the effect obtainable from the second aspect. As a result, a wide angle of visibility can be maintained and the display area of the display device can furthermore effectively be used.
According to a sixth aspect of the present invention, it is preferable that the concave lens has a convex shape on one side thereof and a concave shape on an opposite side thereof facing the display screen. The foregoing switch structure facilitates correction of the lens aberration of the optical portion, in addition to the effect obtainable from the second aspect.
According to a seventh aspect of the present invention, it is preferable that the operation plate has a structure that only the optical portion is formed of a transparent member, and the switch depressing portion and the pivotally supporting portion are formed of a light absorbing member. The foregoing switch structure has the structure that light beams among light beams made incident on the optical portion which pass through optical paths formed toward the switch depressing portion, the rotatively support member and the operation member are not reflected by the end surfaces, in addition to the effect obtainable from the first aspect. Therefore, occurrence of any ghost can be prevented.
According to an eighth aspect of the present invention, it is preferable that the optical portion is provided with a non-reflection portion for preventing reflection of incident light, the non-reflection portion facing the display screen. The foregoing switch structure for a display screen has the structure that light made incident on the optical portion are not reflected by the surface of the optical portion adjacent to the display screen, in addition to the effects obtainable from the first to seventh aspect. Therefore, lowering of contrast can be prevented and, therefore, the display quality can be improved in addition to the effects obtainable from the first to seventh aspects.
According to a ninth aspect of the present invention, it is preferable that the optical portion has a surface provided with a smoke layer. The foregoing switch structure has the structure that the contrast can be raised when electric portion has been supplied to the display device and a smoke effect can be obtained to improve the appearance of the display screen of the display device when supply of electric power to the display device is inhibited, in addition to the effect obtainable from the first to eighth aspects.
According to a tenth aspect of the present invention, it is preferable that the switch structure according to any one of the first to ninth aspects further comprises a switch portion that includes the switch body and the operation plate, wherein the display screen of the display device has a switch-information display area on which the image indicating the switch information is displayed and the other-information display area on which the other information is displayed, so that at least two kinds of information are displayed on the display screen, and the switch portion is disposed above the switch-information display area of the display screen. The foregoing switch structure for a display screen has the structure that a portion of the display screen of the display device is assigned to switch information and switch information is combined with the switch portion so that the single display device has both of a switch information display function and another-information display function, in addition to the effect obtainable from the first to ninth aspects. Therefore, the necessity of mounting two display device can be eliminated. Thus, the overall size of the apparatus and its cost can be reduced.
Other objects, features and advantages of the present invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.